package contest;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.BitSet;
import java.util.InputMismatchException;

public class Q297 {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		// 貞子ォ！ C君そこはもっと頑張ろうよ
		int n = ni();
		int u = ni();
		int[] a = na(u);
//		Arrays.sort(a);
//		for(int p = 0, q = u-1;p < q;p++,q--){
//			int d = a[p]; a[p] = a[q]; a[q] = d;
//		}
		int v = ni();
		int[] b = na(v);
		boolean[][] g = new boolean[n][(n+v-1)/v*v];
		for(int i = 0;i < n;i++){
			int tb = i / v;
			int val = a[i % u];
			for(int j = 0;j < v;j++){
				if(val > b[j]){
					g[i][tb*v+j] = true;
				}
			}
		}
		out.println(doBipartiteMatching(g));
	}
	
	public static int doBipartiteMatching(boolean[][] g)
	{
		int n = g.length;
		if(n == 0)return 0;
		int m = g[0].length;
		if(m == 0)return 0;
		int[] im = new int[m];
		Arrays.fill(im, -1);
		BitSet visited = new BitSet();
		int matched = 0;
		for(int i = 0;i < n;i++){
			if(visit(g, i, visited, im)) {
				visited.clear();
				matched++;
			}
		}
		return matched;
	}

	public static boolean visit(boolean[][] g, int cur, BitSet visited, int[] im)
	{
		if(cur == -1)return true;

		for(int i = visited.nextClearBit(0);i != g[cur].length;i = visited.nextClearBit(i+1)){
			if(g[cur][i]){
				visited.set(i);
				if(visit(g, im[i], visited, im)){
					im[i] = cur;
					return true;
				}
			}
		}
		return false;
	}
	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
	}
	
	public static void main(String[] args) throws Exception { new Q297().run(); }
	
	private byte[] inbuf = new byte[1024];
	private int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}